Thermoresponsive device



May l1, 1943. v

H. c. GRANT, JR A 2,318,607

THERMO-RESPONS IVE DEVICE Filed June 29, 1940 4 Sheets-Sheet l W im, NEY

May 11,1943.v H. C. GRANT, JR 2,318,607

THERMO-RESPONS IVE DEVICE Filed June 29. 1940 I 4 Sheets-Sheet 2 INVENTOR Harig 6T {rw-Un May11, 19 43. -H ..GRANT,JR 2,318,607

THERMO -RESPONSIVE DEVICE Filed June 29, 1940 4 sheets-sheet s mvENToR v Yym] a Grunt Jr:

Mayu, 1943. H. c. GRANT, JR 2,318,607`

THERMo-REsoNsIvE DEVICE Filed JuneI 29, 1940 4 Sheets-Sheet 4 i lmllm INVENTOR Hx, a a'mfaf NEY Patented May ll,

TEERMOBESPONSIVE DEVICE Harry C. Grant, Jr., New York, N. Y., assignor to Specialties Develclilnent Corporation, Bloomnell, N. J., a eol'lwration of New Jersey Application June 29, i940, Serial No. 343,271

16` Claims.

'I'his invention relates generally to thermoresponsive devices ofthe typeV commonly used to control the opening or closing of electrical circuits such as are employed, for example, in electrically operated re detecting, nre preventing and fire extinguishing systems.

More speciiically the present invention has reference to thermo-responsive devices constructed to normally restrain a circuit closing or opening element from completing or interrupting a circuit, and which, upon attainment of a dangerous predetermined temperature, operate to aifect the circuit at any one oLa number of points wherever such devices have been placed, to thereby eilect a suitable signal or other desired operavantage in thatk the accidental failure of the strand would result in an undesired operation of the system, with the attendant danger oi leaving the system unguarded. v

The present invention solves this dimculty by providing a subdivision oi the circuit controlling and the heat-responsive element corresponding thereto into a number greater than one, so that the failure of any one of the heat responsive elements or oi' a number less than the total is inconsequential so tar as the operation o! the device as a whole is concerned.

It is accordingly an object oi this invention to eliminate the possibility of accidental operation by providing an arrangement for a thermo-responsive device oi the type referred to, in the nature oi a subdivided control element.

It is, furthermore, another object oi' the present l invention to provide a device of thetype stated yhaving a subdivided circuit controlling element so constructed and arranged that an operation' i of all sections thereof is necessary to completely bridge or interrupt a given circuit.

Another drawback o!y prior devices may be ascribed to the fact that ordinarily the circuit controlling member is restrained from operation v by the heat-sensitive element againstthe force oi a spring, which, upon failure of said element provides the driving power to eiiect the opera tion. In connection therewith, the heat-responsive eiement, being under 'constant stress, has .been known in-many cases to become suiliciently deformed after a period of time to lead to an undesired operation of the device.

In view thereof, it is also an object to provides .device oi' the character described in which the dmounted and dismounted in a matter of seconds and with the utmost simplicity.

Another object is to provide a device oi theV above stated character, the destructible elements of which are quickly exchangeable as a unit without the replacement oi the device as a whole being necessary.

Still another object is to provide a device as above which is rugged, simple to supervise and to service, and is less liable to accidental failure and undesired operation than devices employed heretoiore.

'I'hese and other objects of the invention, not specifically enumerated above, will be apparent as the invention is described in greater detail in connectionv with the accompanying drawings, wherein:

Figure l is a view in partial vertical section of a. thermo-responsive circuit closing device in accordance with the present invention, the section being taken on line I-l oi Figure 2 and looking in the direction of the Figure 2 is a side view ot the device of Figure l,

' the lower portion being 'shown in section.

Figure 3 is'a partly sectioned side view oi an alternative construction o! the 'device of Figures 1 and 2.

Figure 4 is a view oi a horizontal section ci the device of Figure 3 taken on the line 4-4 looking upwardly, while Figure 5 is a view of the same downwardly.

Figure 6 ,is a diagrammatic layout of a typical circuit incorporating the device oi Figure l.

Figure 7 shows schematically the arrangement oi a device in accordance with the present invention having three subdivisions ot the circuitA section looking .controlling element, and

vmain receptacle or junction shell for the elements of the device connecting the device tothe controlled circuit. Into this shell,.there are led in 4carries the lament anchor members 33.

from the side of the device furthest from the observer electrical terminals 2, 3, and 4 which through wires 5,5, and 1 are connected to contacts 8, 9, I and' II. These contacts are supported by a non-conducting contact plate I2, which is seated on a shoulder I3 formed in the wall of the shell I. The contacts 8 and II are electrically tied to their common terminal 4 through the medium of the wire 6.

Ths contact plate I2 is held in place on the shoulder I3 by an annular extension I4 of a shell cover I5, a coupling piece I6 serving to unite the shell and cover through the medium of cooperating threads I1.y The cover has suitable recesses I8 and I5 which accommodate two circuit closing plungers 2li and 2i, made of non-.conducting material. Each plunger comprises a plunger shell 22, and an electro-conductive contact member 24 loosely carried on a rivet 23 secured to shell 22.

This loose arrangement is resorted to so as to obtain a good contact regardless of whether the plunger comes down-squarely or not.

A non-conducting cylinder 25 lnsulates the plunger assembly with respect to the shell cover I5. The plungers 20 and 2i are formed with a `shoulder 26 to provide a supporting surface for an expansion sprl-ng 21 which with its other end bears against the inside of the top of the cover I5. The plungers are recessed axially at 28 to permit the cemented anchoring, at 29, of one end of a heat-responsive strand 30. This strand may be of any natural or'synthetic iilament-shaped material, such as cotton, silk, or Celluloid, or any other suitable material, that will disintegrate upon being exposed .to a given high temperature. The filaments 30 of which there are shown only two in this case, throughs suitable opening in the roof of the shell cover I5, pass upwardly and are held anchored at their upper ends at 3l in a recess 32 of plungers or anchor members 33.

It is to be understood that the number of strands shown herein is illustrated and is not 'meant t`o limit-the scope of the invention, as will appear later. l

Rigid uprights positioned atop of the cover I5 serve to support an anchorage body 36 which Expansion springs 31 are placed between the body 36 and each of the anchor members 33 to provide' a yielding support therebetween. -A\ cap 33 is placed over the anchorage body 36 for its protecf.

' closing member. Over a period of time, as the 4strand stretches, the upper and stronger spring takes up the slack with the result that each of the upper plungers 33 is lifted upwardly while each of the contact members 24 on the lower plungers is maintained at approximately the same distance from the contacts.

When the strand fails, the contact member carriedby the lower plunger will act in a predev`termined manner in spite of any possible elongation oi.' the strand. Y

In Figure 2, the side view of the device of Figure 1 is shown sectioned in' the main shell only, the reference numbers shown corresponding to the same elements as in Figure 1. the shell has been left out as it would not add to the clarity of the View. An electrical outlet plug 39, having connecting studs 40 for the terminals 2, 3 and 4 is secured into the shell `I and is pro vided with quick threads 4I for connection to a corresponding electrical circuit' outlet.

In Figure 3, the shell I shown comprises two pieces held together by a bolt arrangement 42, so

as to facilitate the assembly inside the device. The shell cover, in this case, is made of two separate halves, one of which is shown at 43. Plungers 44 and circuit bridging contact members. 45 may be integrally formed, the shell cover d3 being non-conducting. It is, of course, understood that the contact member and the plunger may be made of two separate pieces in any one of a number of possible ways, and as already suggested in Figure 1. Anchors 46 for the lower ends of the strands 30 may be adjustable relative to the plungers by means oi the threads 41 within the plungers, thus making possible regulation of the tension of the filaments. An aperture 48 through the contact members permits the introduction of a tool therein to aid in such an adjustment. The upper ends of the strands are anchored in appropriate recesses 49 in an anchorage body 50 which also consists of two halves, one of which is shown. The spring support for the upper anchors has been here dispensed with, since in the case of a very short filamentI the elongation thereof is not as consequential as that of a long one, and the filament ltension is capable of being regulated as shown. f

At 5I and 52 are indicated cross bolts which serve to hold together the two halves respectively of the shell cover 43 and the anchor body 50.

Uprights 35, in this as well as in the construction of Figure l serve-not only to-support the upper anchorage body but also to give protection to the filaments against mechanical injury. The shape and nature of these protective and supporting members may take any desired form aslong as they do not interfere with the primary function of the iilaments which is to be properly exposed and responsive to a given ambient temperature.

In Figures 4 and 5, the reference numbers indicated relate to elements already explained.

In the diagrammatic circuit layout of Figure 6, A and B, and A' and B' have reference to the two subdivisions of two thermo-responsive devices as described above, 24 and 24 being the circuit bridging members as in Figure 1, adapted to bridge contacts 8 and 9, and I0 and II; and 8' and 9', and I0' and II', respectively. At 53 is indicated a source of E. M. F., and at 54 is seen a signal lamp, while 55 and 56v refer to the main circuit wires from the E. M. F. source to the lamp and back through contact bridges 24. The numeral 51 designates a test switch, ordinarily in its neutral position at 0, which, upon being placed into position A" or B" lenables elements A, A',

and B and B to be tested for the failure of their heat-sensitive laments through test wire 53 as will be shown at another point.

The device shown in the diagram of Figure 7,

is essentially the same as that described before, except that it is shown to comprise three subdivisions of the circuit control element rather than twoas before. The numbering of the elements corresponds to thatof the previously described gures, where 2 and 3 are the main circuit terminals, 30 the thermo-responsive strands, and 2 The wiring in the circuit bridging members, as before. The circuit bridging contacts are numbered Il to Il.

In Figure 8, the schematic circuit layout incorporating a closed circuit and a. triple-element device. has reference to elements similar to those of the preceding figures, except that the indicating lamp circuit, comprising wires Il and Il, .is controlled vthrough the medium of Velectromagneticrelays il. I and ILratherthandirectly by means of members 24 as before which are-biased toward open circuit in this case. Wires 'Il and 'H through the normally closed circuit bridging members Il sumly current from the E. M. F. source Il to the three relays, thus holding open contact points 12, 'Il and 14.

The operation of the device is quite apparent.-

an exposure-to a given high temperature, having as a consequence the practically instant failure of remaining'strand will operate and thus complete the circuit. It is, of course, obvious that within practical limits, the number of strands and circuit control member subdivisions may be increased to any desired extent, naturally. including appropriatemodiflcations in the general design of the device and the attendant circuits.

Should, after operation of the device, a replacement of the iilaments become necessary, a iooseny ing of coupling member Il will permit replacement, as a unit, of the shell cover Il including the plunger and upper anchorage assembly, enabling the system to be made ready for another indication on very short notice and without the necessity for any particular skill.

With safety systems of the type referred to, it is generally the custom to subject them periodically to check-over tests for the purpose of asceropen by the energized relays Il, ll and 1' to'close the circuit through indicating the 'lamp N.

From the foregoing it will be seen that the invention as described above embodies the important objects pointed out at the beginning, providing, as it does, a thermo-ve device for the detection of nre and high temperatures which is exceptionally dependable; which, by the ex- 1 pedient of subdividing the thermo-responsive circuit controlling element provides an insurance against accidental failure, an indication of a predetermined condition being almost always obtainable; which, by incorporating filament tension adjustment facilities prolonga the de'- pendable life of the device and materially reduces the possibilityof premature operations; a device which is easily put into a state of preparedness afterv having operated and without the necessity of disturbing any circuit connections, and which lends itself to simple and effective supervision.

However, while the invention has been described in connection with the details of construction shown in the accompanying drawings. it will be apparent to those skilled in the art that the invention can be embodied in other forms of construction without departure from the scope of the invention, and for this reason I do not wish to be strictly limited to the disclosure but rather to the scope of the appended Iclaims.

I claim:

1. A thermo-responsive device comprising in combination, electrical current conducting means composed of a plurality of separately additive portions forming an operative unitary whole, electrical circuit contacts associated with each of said portions, means urging said subdivisions into an ultimate desired position with respect to said contacts, and a separate substantially identical taining their state of preparedness. Since, in

the embodiment of the invention as shown in Figure 1, the failure of both nlaments is indicated automatically, it is only necessary to obtain an indication when desired. of the failure ofl either of the strands. This is accomplished by means of the test switch Il and the wire 58 to which are connected the contacts l and il", as in Figure 6. It is'seenthat an indication will be obtained, for instance, if portion A of the device has operated byv shifting the switch II to position A", the current going from one side ofthe E. M. F. source through the lamp Il, thetermina'l l, the contact lathe control member Il, the contact |I,to the terminal I, through thewire I8, the switch Il, the contact A", and back to the other side of the source I8. Similarly, an indicating circuit is established through the contact B", should the portion B of the device have operated' due to failure of its filament. The function of the device of lliguze 'l is obviously to close the circuit between terminals 2 and 8 when-failure of all three strands Il vhas ocwhile the circuit of Figure 8 requires all three circuit bridging elements Il to movel into open circuit position to interrupt the three paralthermo-responsive member associated with each of said portions normally restraining said subdivisions from assuming said ultimate position, whereby upon the exposure of said members to predetermined temperature conditions all of said portions assume the desired position with respect to said contacts tio-complete a desired Operative position of said conducting means.

2. A thermo-responsive device comprising in combination, kelectrical current conducting means composed of a plurality of separately additive portions forming an operative unitary whole, electrical circuit contacts associated with said portions, means urging said subdivisions into an open circuit relation with respect to said contacts, and a separate substantially identicalV thermo-responsive member associated with each Aclosed circuit relation with respect to said contacts, and a separate substantially. identical thermo-responsive member associated with each of said portions normally restraining said portions from assuming said closed circuit position. whereby upon the exposure of said members to predetermined temperature conditions all of said portions assume said closed circuit position with respect to said contacts to eiect a complete closed v circuit operation.

4. A thermo-responsive device comprising in combination, -a pair of electrical circuit termi:

nals, electrical current conducting means formed with a plurality of separate subdivisions adapted together and additively to form a conducting bridge between said terminals, means urging said subdivisions into a circuit bridging position with respect to said terminals, and a separate thermoresponsive member associated with each of said subdivisions adapted to restrain said subdivisions from assuming a circuit bridging position with respect to said terminals against the force of said last recited means, whereby only upon the operation of all of said members under predetermined conditions an electrical current conducting bridge is formed between said terminals.

5. A thermo-responsive 'device comprising in combinaiton, a support, filament means adapted to disintegrate upon being exposed to a given temperature, retaining means for each end of said filament means, being slidably disposed in said support for at least one end of said filament means, spring means interposed between said slidably disposed retaining means and said support, electrical contacts disposed in said support, electric current conducting means on the retaining means of one end of said filament means adjacent said contacts adapted to bridge said electrical contacts normally held out of touch therewith by said filament means, and electric current terminals in said support operatively connected to said contacts adapted for connection to an electric circuit.

6. A' thermo-responsive device comprising in combination, a support, two independent fully exposed laments adapted to disintegrate uponbe` ing subjected to a given temperature; a retaining member ,for each end of said filaments, being slidably disposed in said support for at least one end of each of said laments, spring means interposed between said slidably disposed. retaining members and said support, whereby said filaments are'constantly maintained under yielding stress, a pair of electric circuit terminals disposed in said support, an independent eiectric current conducting member on each of two of said retaining members held in a non-actuated position by said filaments, and electric contacts adjacent to said conducting members in said support electrically connected to said terminals adapted in combination with said two conducting members to form a circuit bridge across said terminals upon disintei gration of said lam'ents.

7. In a thermo-responsive device of the type having thermo-responsive iilament means, and electric circuit controlling means restrainedby said iilament means from assuming an ultimate' having thermo-responsive lament means: and electric circuit controlling means restrained by said filament means from assuming an ultimate operative position, the combination of a plurality of iilaments, and an equal number of separate subdivisions for said circuit controlling means associated with said iilaments, said subdivisions adapted together and additively to form said circuit controlling means.

9. In a thermo-responsive device of the type having thermo-responsive lament means, and electric circuit controlling means restrained by said filament means from assuming an ultimate operative position, the combination of a receptacle, a structure supporting the filament and circuit controlling means, and coupling means,- said receptacle and said supporting structure being separately united by said coupling means to form a unitary structure.

10. A thermo-responsive electric circuit controlling device comprising a pair of circuit terminals, circuit terminal subdivision means for each terminal, electro-conductive bridging means for each of said subdivisions urged toward an operative position with respect to said subdivisions, thermo-responsive means having subdivisions, one associated with and restraining each of said bridging means from assuming said operative position, and supporting means for said` -having subdivisions, one restraining each of said subdivided bridging means, and supporting means for said thermo-responsive means.

12. A flame detector comprising in combination a receptacle; a pair of main terminals adapted for coupling to an electric circuit, intermediate terminals connected to said main terminals, common median terminal means for said intermediate terminals, all said terminals and terminal means disposed in said receptacle; supporting means,

said last named means supporting a member to` conductively bridge each of said intermediate terminals with said median means, means urging said bridging member into a bridging position, a name sensitive lament for each of said bridging members and normally-restraining said members, and vretaining means for the ends of said filaments; whereby upon the exposure of said laments to aiiame, a conductive bridge is formed between said main terminals comprised of conductive subdivisions.

13. In a thermo-responsive device of the type having thermo-responsive means, and electric circuit controlling means restrained by said responsive means from assuming an ultimate operative position, the combination with a vpair of main terminals, of intermediate terminals, and

. bridging means therefore adapted to form sep- 'aratelyoperable bridging sections, said sections together forming a conductive bridge for said main terminals.

14. In a thermo-responsive devic'e of the type having thermo-responsive means, and electric circuit controlling means restrained bjy said responsivemeans from assuming an ultimate operative position,the combination with a pair ot main terminals, of bridging means for said termlnals comprising a plurality of separatelyoperable bridging sections-and a thermo-respon# sive member for each of said bridging sections, the operation of all of said responsive members being necessary to completely bridge said main terminals,

l5. A device for the control of an electric circuit, comprising thermo-responsive means hav' ing independent subdivisions, circuit control means comprised of independent control members, one associated with each of said subdi-l visions to be restrained thereby fromy assuming effective only when all otsaid subdivisions have operatively released said control members into their ultimate position.

16. A flame detector comprising in combination, receptacle means, containing a pair of main circuit terminals. a median circuit terminal. and.

four intermediate terminals, two of said intermediate terminals being conductively connected to each other and to said median terminal, the

' two other intermediate terminals being each conof said intermediate terminals, each pair oi'said.

intermediate terminals including one of said conlo ductively connected terminals, means urging each an ultimate operative position, said control being of said bridging members' into s bridging no@ sition, and a name sensitive mament associated with each of said bridging members'normally adapted to restrain said members from assuming 15 a bridging position.

HARRY c. GRANT. .nl

CERTIFICATE 0E coRREcTioN. p Patent No. 2,518,607. May 11, 19M.

Y HARRY c. GRANT, 'JR. 'Y

.It is hereby certified that error appears in the printed pacification of the above numbered patent requiring correction 1s-follows: PagevZ, first column, line h2, for the word ."illustrated" read "illustrative-u; page 5, second column, line 56, and'line'liO-lil, claim l, line 52 andV line Sfr-57, claim-2, and line 68, cla-im 5, for l'subdivisions" read --,portions; and that .the said:Letztem-sV Patent shuid be vremi with this correction therein that -the same may conform tothe recordl of the case in tipe 'Patent Office. Signed and'seai'ed this 25rd day of November, A. n. 1915.

l Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

CERTIFICATE 0F) CORRECTIioN. Patent No. 2,518,607. may 11, 19115.

' HARRY c, GRANT, lm. It is hereby certified that error `appears in the printed ecification of the above nmnbered patent requiring correct-ion as follows: Page?, first column, line L12, for vt'he'word."11mst-.rawcv' read' -111u'strat1ve; pega 5, second column, lin'e 56, and 'line" L10-111, claim i, line 52 11nd line -56-57, claim 2, and line 68, claim 5, for "subdivisions" read -.portions; and 'that .the sam,-Lettez-.tl Patent should be Vread with this correction ther-611i thai; the same may conform to the recordA of the case in tile `Paftent Office. Signed andseal'ea this 25rd day of november, A. D. 19113:, 1

l Henry Van Arsdale, y (Seal) Aoi-,ing Commissioner of Patents. 

